"But if you can't see anything, how can you tell where to steer?" asked Mark.
"By means of this instrument," replied Mr. Roumann, indicating another among the many on the wall of the projectile. "This is automatically kept pointed at Mars, and by means of a hand and dial I can tell how to keep the Annihilator aimed directly at the red planet."
"Even when it is on the opposite side of the earth from us?" asked Jack.
"We are now far above the earth," was the answer, "and the planet on which we lived offers no obstruction to my telescope being pointed at Mars, even though it is daytime, when Mars is on the opposite side of the earth."
"Have we traveled as far as that?" asked Jack in awestruck tones.
"We have come just thirty thousand miles since leaving the earth," replied Mr. Roumann.
"But we don't seem to be moving at all," objected Mark.
"That is because we are shooting through space so fast, and because you can see no stationary objects with which to make a comparison, as when you are traveling on a railroad train," continued the German. "And, as we are not dependent on tracks, or roads, with their unevenness, there is no motion to our projectile, save that of moving through space. That is why it seems as if we were standing still."
"But thirty thousand miles!" cried Jack. "I thought the earth's atmosphere was variously estimated at from only forty to two hundred miles in thickness."
"The oxygen atmosphere may be," agreed Mr. Roumann. "As a matter of fact, the atmosphere we are now in would not support life for you and me a single instant. But it is atmosphere, nevertheless, or my instruments would indicate something different, and my atmospheric motor would not work. No, I expect to be traveling through the atmosphere for several days yet. Then we shall reach the true ether, and the Etherium motor will be put into operation."